#### Answer

$x-y=2$

#### Work Step by Step

If the line has intercepts $a=2$ and $b=-2$ this means it contains $(2,0)$ and $(0,-2)$ .
We need to find the slope now:
$m=\frac{y_{2}-y_{1}}{x_{2}-x_{1}}= \frac{-2-0}{0-2}=\frac{-2}{-2}=1$
Now, with the slope-intercept form, with m=1 and passing through $(2,0)$, the equation is:
$y-y_{1}=m\times (x-x_{1})= y-0 = 1\times (x-2)$
So $x-y=2$